1. Technical Field
The present disclosure relates to ultraviolet irradiation apparatuses, and particularly to ultraviolet irradiation apparatuses for irradiating fluids with ultraviolet light.
2. Description of the Related Art
Ultraviolet light (ultraviolet radiation), particularly deep-ultraviolet light (deep-ultraviolet radiation), which has wavelengths of about 200 to 350 nm, is used in a variety of fields such as sterilization, deodorization, cleaning, water purification, lithography, and illumination for its ability to decompose organic substances.
Mercury lamps, which cause a glow discharge of mercury, are widely used as ultraviolet light sources (see, for example, Japanese Unexamined Patent Application Publication No. 2012-146712). Japanese Unexamined Patent Application Publication No. 2012-146712 teaches the use of deep-ultraviolet light with a wavelength of 254 nm emitted from a mercury lamp to efficiently decompose and remove carbon contaminants deposited on a mask or other component used in an exposure apparatus without damaging its optical system.